1. Field of the Invention
The present invention relates to current sensors, and particularly relates to a current sensor that measures a value of a current to be measured by detecting a magnetic field generated in proportion to the current to be measured.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 4-33542 and Japanese Unexamined Patent Application Publication No. 9-127159 disclose configurations of current detectors.
In a current detector of a servo drive device described in Japanese Unexamined Patent Application Publication No. 4-33542, a magnetic core having a gap for inserting a Hall element therein is fixedly attached to a printed circuit board, and the Hall element is located and mounted in the gap for inserting the Hall element. Each terminal of the Hall element is electrically connected to a terminal of circuit wiring formed in or on the printed circuit board.
A current detector described in Japanese Unexamined Patent Application Publication No. 9-127159 includes a magnetic core having a gap in part of a magnetic path formed in a circular shape, and a magnetosensitive element that is disposed in the gap and detects the density of magnetic flux passing through the gap. A through-hole, through which a current wire to be measured passes, is formed in a printed circuit board. The magnetosensitive element is disposed in the vicinity of a circumference edge of the through-hole. A grounding pattern connected to a ground line is formed on the printed circuit board. The magnetic core is fixed on the grounding pattern with a conductive adhesive.
In the current detectors described in Japanese Unexamined Patent Application Publication No. 4-33542 and Japanese Unexamined Patent Application Publication No. 9-127159, a magnetic body as a magnetic core is arranged on a surface of the printed circuit board. A Hall element is arranged in the vicinity of the center of the magnetic body in a thickness direction of the printed circuit board. In the above configuration, the height of the current detector becomes large in proportion to the height of the magnetic body in the thickness direction of the printed circuit board. This means there is room for further miniaturization of the current detector.